The wine's colour or intensity of colour is mainly caused by anthocyanins. There are trials and methods which take four hours that correlate the anthocyanin content in the grape with that of the wine. However, bulk wine on the market is paid by degree and point of colour and not by mg/l of anthocyanins; furthermore, there is not a high correlation (less than 0.5) between the colour degree and the anthocyanin content. Therefore, at present there is no suitable method for the determination of the intensity of the colour of wine from the grape.